Differentiating American crows and common ravens in the field.

Visual difference between a crow (left) and a raven (right).

In North America, there is a large number of birds entirely black in colour.  They can be found in three different sizes.  Smaller individuals are blackbirds, aptly named, and are usually Brewer's or Rusty blackbirds.  Then there are crows and ravens.  They are medium or large birds that often get confused with each other.  Enormous large black birds are likely one of two species of vulture.

There are approximately 31 million crows present in North America.  They can be found throughout all of Canada (south of the territories) and north of Mexico.  Ravens boast a larger range and inhabit the artic all the way into Central America but are not found in much of the central and east US and Mexico.  I could not find any information on population numbers, however, I believe that there are far more crows than ravens.  A look into the sky at dusk will often provide shocking evidence of this as hoards of crows flock to their roosts for the evening.  Apparently, they are planning a murder.

Ravens are about three times the size of crows.  This can be hard to judge at a distance.  Crows are gregarious in nature and tend to be found in groups while ravens often confer in pairs, male and female.  They mate for life.  Crows have also been known to mate for life.  A sure way of differentiating between the two is to examine the size of the beak relative to the head.  A crow's beak is much smaller than its head while a raven's beak is far larger.  

Another way to separate the species is by their calls.  Crows have a somewhat limited vocalization, the ubiquitous "caw" being a sure identifying feature.  Ravens have a remarkable range of sounds (over 100) and often can be heard uttering low-pitched guttural noises.  Captive ravens can reproduce human language to some extent.

I hope this has helped.

Thanks for reading.

Eric Svendsen     www.ericspix.com